Research And Design Of Small-size Muliti-band Handset Antennas

With the rapid development of wireless communication technology, low-profile,light-weight, multi-band and excellent performance wireless communication devices areexpected by consumers. However, those requirements introduce a huge challenge for theantenna designers, especially under the small-size, not only requirement designmulti-band internal handset antenna, but also has good radiation characteristics. In orderto meet the requirement of modern mobile communication system, the design internalmobile phone antenna should not only include3G and4G wireless mobilecommunication systems operating bandwidth, but also should be compatible with2Gwireless mobile communication system operating bandwidth, to make it seamlessbroadband communications within the entire operating bandwidth. Therefore, researchand design of small-size and multi-band internal handset antenna is great significance.First of all, the paper introduces the development course and research backgroundof mobile phone antenna. The theoretical analyze the relationship of mobile phoneantenna’s limit Q value and antenna size, the relationship of antenna Q value andimpedance bandwidth as well as antenna far filed radiation characteristics.Then, the paper detailed introduces theory of balanced mode and radiating mode,theory of characteristic modes and decoupling theory of multi-input multi-output(MIMO) antenna. Among them, using theory of balanced mode and radiating mode fora reasonable design multi-band internal handset antenna; using theory of characteristicmodes for a reasonable selection of the antenna’s feed point; when design multi-inputmulti-output (MIMO) antenna, decoupling theory of multi-input multi-output (MIMO)antenna tells us how to effectively decoupling. Above these theories provide detailedtheoretical support for handset antenna design.Moreover, according to internal handset antenna design difficulties and hot spotsnowadays, the paper proposed three novel internal handset antennas: the first belongs tothe small-size of the plane print structure octa-band internal mobile phone antenna, theband including LTE700/GSM850/900/DSC/1800/PCS1900/UMTS2100/LTE2300/2500;the second is the lower band GSM850/900reconfigurable small-size internal handset antenna, meanwhile the upper band cover DCS1800/PCS1900/UMTS2100/LTE2300/2500; lastly， a multi-input multi-output (MIMO) internal handset antenna is designedin order to satisfy4G wireless communication system. These antennas are coupled-fedtechnology，the advantages of low cost, easy processing and excellent performance canbe mass production.Finally, operating principle of these proposed internal handset antennas have beendetailed analyze, and they have been fabricated and measured in order to confirm theirperformance, the HFSS simulated results coincide well with measured results.